Opus and BMW (e46)

05-13-2004, 12:02 PM

I'm waiting on my Opus ... but I started planning the wiring... now I need to tap into a ignition source to let the Opus no when to turn off/on, right?

Unfortunatley, all of the ignition sources in the e46 (the current 3 series) turn off while cranking... this is a problem isn't for the Opus .. Part of the appeal of an Opus is that it survives cranking .. say I'm parked somewhere with the carputer on, decided to start the car, the ignition source will turn off when I crank, the Opus will signal the shutdown, then the car will statrt, ignition back on .. will the Opus then signal a startup? What will happen?

It should work fine. There is a programmable delay between the time when your ignition lines goes low and the Opus signals the motherboard. As long as the ignition line goes high again, the Opus will never send the shutdown signal.

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Very cool product. I may try this. only $10 and no need to cut into my 2004 bmw. Thanks. I am assuming I have to use the fuse in a "ACC on" fuse for the ignition to turn on the accessory. i am also assuming this will handle the opus power

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Very cool product. I may try this. only $10 and no need to cut into my 2004 bmw. Thanks. I am assuming I have to use the fuse in a "ACC on" fuse for the ignition to turn on the accessory. i am also assuming this will handle the opus power

Grabbing the Acc from the fuse panel is fine, just be sure to grab the protected side of the fuse so your Acc lead is protected from shorts too. Don't want to run a screw through the lead and smoke something further up the line.

Opus (and many forum members, including myself) do not reccomned taping the fuse panel for the main power lead of the Opus. The Opus documentation recommends main power be taken directly off the battery. One of those "Best Practice" things.

Oh, yeah, don't forget to fuse the main power lead CLOSE to the battery. 6 inches or less is a good rule of thumb. (10 amp for the Opus 90, 15 for the 150).

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thanks Phil. I see what you are saying about the power lin from the opus to the battery. i will be running the power to the battery through a distribution box with an inline fuse right next to the battery. I was going to run the ACC or ignition ON cable to the fuse box. Does this make sense?

One other question along these lines. My battery for the car is in the trunk (lucky me) and I have pretty short runs to my car audio and PC setup in the trunk i was wondering about my grounding options. I know most people say ground as close as you can. I was curious if I could run all of my ground to s distribution box and ground the box to my car battery. Is this safe? i would say the total length would be a few feet. Thoughts?

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Yes the ACC line is easily available at the factory amp harness in the trunk or in the headunit harness. I was running a lot of wires anyway, so I took it from the HU harness.. It took running a wire all the way to the trunk, but like I said, i was doing it anyway... The good news about wiring up an OPUS in any BMW is that the battery is already there in the trunk so you don't have to run cables for the other wires more than a couple of feet